As candidates on both sides of the aisle lament the increase of the income gap and slow wage gains, WSJ chief economics columnist Greg Ip examines the central role of weak productivity. Photo: AP

This transcript has been automatically generated and may not be 100% accurate.

... well the elections The and a half away still but it's not too early to see what the big economic issues going to be ... and that's when he does the fact that they're just not doing very well ... and Jeb Bush complains that the average family has had a reason fifteen years ... Hillary Clinton men's wages eight times in her big economy speech ... what's interesting is that people generally I'm not talking about probably the single most important room in wages over the long run ... in us proximity ... how much goods and services that each worker produces per hour ... it's been growing very slowly the last few decades ... now it is true ... that wages have been growing even more slowly than productivity ... to some people say we need to re distribute from the most productive and the riches to those who are less well off ... but if you look in recent history you do find that ... it's still the case that would proximity is stronger almost equal solar real wages ... so if you look of the last term Bill Clinton for example he benefited from both low unemployment and strong productivity growth and was a great time for the average worker ... by contrast ... Brock Obama has had a struggle with extremely high unemployment listen to the last year so ... and we productivity ... as a major reason why wages are doing as poorly as they are now ... I think that the candidates need to pay more attention to sit with the product of the what they can do to raise it ... the solutions aren't easy we don't really know what Dr proud to be the long run ... but until we actually start to address it ... directly ... it's not going to get the attention it